In reviewing the prior art preparatory to determining the novelty of our invention we have come across a number of prior art patents relating to solar heaters and the like. Some of these prior patents use elements which we employ in accordance with our invention. However, the prior art patents utilize these common elements in a different way and do not succeed achieving the advantageous and efficient recovery of heat which we achieve when practicing our invention.
Although we mention some of these prior art patents hereinafter, we do not feel that these prior art patents in any way relate to our invention and a discussion of the features which follows hereinafter is intended only to provide a brief acknowledgement of some of the techniques which have been heretofore employed.
For example, H. E. Thomason in U.S. Pat. No. 3,369,539 of Feb. 20, 1968 reveals a system in which solar rays enter a solar heat trap or collector through a substantially transparent cover arrangement, the rays striking a heat collecting layer of bits of material such as sand or blue stone chips, with or without an asphalt, coal tar or similar blackening binder. The granular material was found to have a tendency to slide or creep or flow towards the bottom of the collector. This problem was overcome by using mesh to prevent sliding or creeping. Water is flowed through the trap to remove heat and it is stated that if the mesh is wire or other heat conducting material, it aids in transfering heat to the water from the heat collecting material.
T. B. Modine in U.S. Pat. No. 2,274,492 reveals a heating device with a substantially flat heat transfer element comprising a pair of substantially parallel inlet and outlet pipes and a plurality of smaller cross-tubes connecting these pipes for the passage of fluid to be heated from the inlet pipe to the outlet pipe. In this arrangement a plurality of fins extend between and are rigidly secured to the cross-tubes. These fins are substantially parallel with the common axial plane of the pipes. A container is provided which encloses the aforesaid element consisting of a bottom, a glass top and side and end members. A layer of heat insulating material is positioned between the heat transfer element and the above-noted bottom.
O. H. Mohr in U.S. Pat. No. 2,122,821 has as an object the improving and simplifying of the construction and operation of solar heaters. A heater is provided which consists of a series of spaced upwardly inclined tubes connected at their upper and lower ends by headers, the tubes and headers being made of a metal such as copper or the like having a high coefficient of heat conductivity and being painted or colored black to absorb the greatest amount of heat possible when exposed to radiation. Mohr provides a housing or box for the receiving and support of the heating tubes and headers, the box being insulated to retain heat and being covered with two or more layers of glass with an intermediate dead air space to reduce conduction losses to a minimum. There is further provided an arrangement of tubes and heaters which not only function as a solar heater but also as a hot-water storage reservoir. An auxiliary heater is employed for heating and circulating water in the solar heater when necessary. A winding is provided within the housing whereby both direct and reflected radiant energy is utilized in between the tubes and headers.
According to U.S. Pat. No. 2,208,789, B. H. Cally provides for a construction of a solar heating unit in such a manner that smaller heating tubes are used than were previously employed and novelty is provided in joining the tubes with header pipes of a larger diameter in such a manner that the speed of circulation may be any predetermined speed deemed necessary for proper heating of the water.
According to U.S. Pat. No. 3,514,942, W. F. Kyryluk provides a solar heater transducer including a transducer element having an outer member of a material transparent to solar radiant energy rays in combination with an enclosure with a space defined in between an inner side of the transducer and a wall of the enclosure, with a fluid heated by the transducer positioned in the enclosure.
G. Meckler in U.S. Pat. No. 3,369,540 bases his invention upon the discovery of apparatus for preventing or minimizing the thermal load normally imposed on the air conditioning system of a building due to external natural light sources. In accordance with his invention, Meckler provides a multisheet light transmitting structure which is capable of absorbing a substantial amount of solar energy which it would otherwise pass therethrough and which is capable of dissipating this energy while minimizing the increased heat load in the building.
F. M. Kiser in U.S. Pat. No. 2,167,576 provides a cover or hood formed of a material adapted to concentrate the sun's rays upon a water heating tank. The size and shape of the hood is determined by the hot water requirements and the hood preferably comprises upwardly inclined glass side walls, glass end walls and a glass top wall, the walls being connected together and reinforced at their intersections by angle iron strips.
While the above patents refer generally to solar heating and solar heating systems and panels and while these patents furthermore use individual features which we also employ in the present invention, they do not achieve the effectiveness of solar heat recovery which is achieved in accordance with the instant invention and consequently are not anticipatory thereof.